Improved resin-to-dentin bond strength and durability via non-thermal atmospheric pressure plasma drying of etched dentin

This study aimed to evaluate the improvement in strength and durability of the bond between dentin and composite resins following plasma drying of the etched dentin surface using non-thermal atmospheric pressure plasma. Plasma drying was applied to the etched dentin before applying adhesive. Conventional wet-bonding and helium (He) gas-dried bonding schemes were used as control groups. The bond strength of the composite resin to dentin was measured as the microtensile bond strength at 24 h after bonding and after 10,000 cycles of thermocycling. Hybrid layer formation was observed using micro-Raman spectroscopy and scanning electron microscopy. Although the bond-strength values were not statistically different either at 24 h after bonding or after thermocycling, the bond strength of the plasma-dried bonding group was significantly higher than the conventional wet-bonding group and He gas-dried bonding group. Micro-Raman spectral analysis revealed effective penetration of the adhesive and an improved polymerization rate of the adhesive after plasma drying. Plasma drying increased the penetration of hydrophobic resin into the collagen mesh structure, which improved mechanical bonding and long-term durability between dentin and composite resin.